The performance variables of paper substrates vary greatly themselves depending upon the vast array of end-uses for such substrates. However, most performance variables may be programmed in a paper more readily as the dimensional stability of the substrate increases. Therefore, for a very long time, it has been desired in the market to supply a dynamic paper substrate having superior dimensional stability, yet being capable of having high surface strength.
Lipponen et al. (2003) “Surface sizing with starch solutions at high solids content”, TAPPI Metered Size Press Forum, discusses the use of size-press applied high starch solution solids that may be used to gain surface strength in some very select cases, but fail to achieve and/or appreciate the importance of a dimensionally stable paper substrate. Further, the papers described in Lipponen et al., have what the authors describe as undesirable low internal strength (not lower than about 140 J/m2).
In addition, a subsequent paper by Lipponen et al. (2005) “Effect of press draw and basis weight on woodfree paper properties during his solids surface sizing”, TAPPI Spring Technical Conference & Trade Fair, the authors discuss methodologies for increasing the undesirably low internal strength of a paper substrate containing size-press applied high starch solution solids thereon. Unfortunately, these references are representative of failing attempts to provide a paper substrate having high dimensional stability and high surface strength all at once.
Accordingly, there is still a need for a low cost and efficient solution to increase dimensional stability and surface strength of a paper substrate.